Method of proofing tubes



Aug. 7, 41945.

G. E. STEIN EL METHOD oF PROOFING TUBES Filed Aug. 25, 1941 6/ Y l/Emea GEORGE ESTEINEL.'

, @WMP ATroRNEYs Patented Aug.' 7, 1945y l I l Y' George lSteineI,-Barbertonf!Ohioffassignor tok The Firestone Tire' & Rubber Company, Akron,

l c hio,a corporation'of Ohio l nventionerela'testo methods ofl proofing tu nesifialnd more especiallyt'relates to improved pi' oeil'ure vfory applying vpmoiing composition. to terior surface of'enfdl'ess:rubber tubes. sinvention is of primary utility in the rub-y ber industry for the manufacture of rubber inner tubes lof theleakprooi type. An inner tube of c ef character mentioned hasits interior $111'- ,ace' treated with proongcornposition to pre- Ventthe diffusion of air through its rubber strueture. Inthe manufacture of such tubesa de'nite to et even distrioution ofi the'jprooiina come p" ition upon theentire interiorsurface of the.

tube anditis to,the1:ei'ift`i1mir-1gv of thisoperation that this invention primarily directed.

vThee ""fjobjectof the invention isvto effect an even distribution oi? the proofingcomposition. More rspecica1l'y,' the inve ntion. to@ lapply 'pressure' Ito" vtl'ie tube progressively; anevenlSzf to Applieationxugustjzs, 1941, lSerial No; 408;-1'27 zrolainis..y (c1..-1.54-ei5i t l s Y 'rnerearterztne flattened tubeissubjeoted to spread evenly overtheentire interior-'survno alliparts ofthe tube notwithstanding'variations the'transverse thickness of fthe tube.` Another object isvzto vassi'ire that proofing compositionwill cover the splice off an endless rubbertube. Other lobiet'zts Will'be manifest as the descriptionpro Cdss y 's Otthelaccompa'nying,drawing: u j Fig. 1"is afperspective View of one endportion of a"ru`bbe'r tube showing .proofing composition Ibeing. placed therein; y y s l f Fig'. 2is an elevation of the tube;y afteritlhas beenffsplficed to endless 4form ,withn the rprofiting ,ir'rri'p'ositoritl'ie'reilfl;l i

a 'Figsfis va front elevation of apparatus `for pro.- gressively applying pressure` toy the i Ihe improved:method constituting thefinventionI may be statediasfollows:v The material from lWinch ytlieinner, tubes are made isv extruded, in

f t-plasticunvulcanized form, inacontinuousstrip,

stripis` a flattened tube. As thel strip.I is

endless tube face' of tlietube; progressively 'around the latter'. completes the proofing operation, so that thereafter a'val've steinlmay loe mounted in the tubeand tiiela'tter vulcanized by heat and'pres- Surein thesualmariner. h f

Attention now isy directed to Fig'. '3,and1Fi`g, 4 of the-drawing' Wlierfein is shout/ny apparatus that may beeinnioyed'ror -oarryi'ng;-out trietulo-eepressing'op'er'atibn o'f 'the previously d'escribedm'ethod. Said? apparatus comprises a lower housing struc'- tureA I'4`,'.`and" an uppenl'i'ousing structure l5 of somewhat smaller' sizes'uperposed thereon. Mbunted'upon tl'iefront'wall of lthe`upper''housing 15,1 andJ projecting' forwardlvand iateraiiy" there'- 'fr'ornis anlovernanging tnenne is'. of rectangular shape'i f Joura'lie'df in the front" and rear'm'enib'i's ojf'jt e Affar'ne 1'6" is a "didi/erflio'ri'"zoiitall shaft r1', shaft a roller" IB'i-`1Xedthereon; said shaft" being disposed in"` the" central fore-and-aft planeet,M the upp'erho'usiiigvthe' roller I8 con'- stitutiiigone of'trie A'presser rollers ofthe apparatust, Jourhaledi theffranie 116,' parallel tothe siiaift Hand aA iitti'e' toft'nejrigiit' thereof as viewed from the front off tine:app'aratus ,Vr is an" idler spart izerupony which is mounted a morality of axially spaoed apart peripnerauv grooved sheaves, suon tite sneavezu. At the' extremerignt end o'f Ap ducedtvit isdtransversely severed intoshorter its, eachoflthe proper. length to producean ind idual-inner tube, such a. unitbeing shownat c ANeiman operator; holds opent one end o the tubeunit i0, and. pours*v orl injieets aideteryiniziate quantityof proofing. composition into vthe interior thereofy, which operationl is conventiontally'shownT Fig. 1...y Immediately. .thereafter-the operatoijloins-v thel two ends: of t thee tube unitby a lapped or butt splice tog produce an `endless tube :structure iflg,1!ig; Zshaving a closed internal chamber in which the proofing compositionv is contained, the splice being shown at l2 in said 'rangeinentenabiinjg the ne1ts`z3 to be maintained 'atitiiedesired'tautness:

s Upn'tlieenci' of AShaft l-'I"`nearest"tl"ie upper housing llislasprdcket 2.1;, Fig. 4, and'asimilar' Ysprocket(notfsliovvn) isk mounted upon the .endl of" ,shaft iff;x y,.'Ira'ine'd' about' saidsprockets *isa*v sprocket. chain 28 for driving the same and chan having.; drivingA engagement with suitable dri ing",meansfsuchasV an electric motor (not The lowervsreach of 4said sprocketchain' the concurrent driving of the roller I8 and the conveyor belts 23, the upper or work-receiving reaches of the latter moving toward the'right as viewed in Fig. 3 whereby work` pieces deposited thereon will be conveyed to the right hand end of the frame I6 and dropped off the end thereof.

Any suitable conveying means (not shown) may be provided thereat for receiving the work pieces and for delivering them to any desired destination for further processing.

Adapted to cooperate with the driven roller I8 for effecting the progressive pressing of the work v3I is in elevated or vertical position. The op- .erator first mounts the endless rubber tube II,

is a presser roller that is designated as a whole by the numeral 3I, and which commonly is known as a contour roller. This roller has a horizontal operativel position over thev roller I8 and parallel thereto, as shown in Figs,v 3 and 4, and has a vertical inoperative position (not shown) in which it is positioned within the upper housing I5, the latter having a large opening 32 in its front wall that enables the roller to` move therethrough. Said contour roller 3I comprises a nonrotatable bar or rod 33 that is mounted at one end in a bracket 34, the latter being pivotally mounted in a supporting structure (not shown) disposed Within the upper housing I5. The rod 33 carries end plates 35, 35 between which are mounted on the rod a plurality of discs or washers 36, 36, each of which has an axial aperture substantially larger than the rod so that the discs are capable of movement to eccentric positions relatively of the rod, as well as rotary movement about the rod. A guard member 3'Isupported at one end by an arm 38 secured to the free end ofthe rod 33 and at the other end by an arm 39 formed on bracket 34 is provided for limiting the eccentric positions of the discs in one direction. Means (not shown) is connecte-d `to the bracket 34' for swinging the contour roller between the operative andthe inoperative positions aforementioned.

` The construction of the contour roller 3l is `such that when it is lowered upon a work piece, such `as the endless unvulc'anized rubber tube with proofing composition therein, upon the idler rollers A4,2the lowermost portion of the depending tube ,resting upon thev driving roller I8. As soon as the work is properly positioned as described, the operator actuates the proper instrumentali- 4ties to lower the contour roller 3I and to start roller I 8. Due'to the pressure of the contour roll- Structure II, the roller willexert uniform pres- Y sure on a transverse region of the tube notwithstanding theirregular thickness of the flat'- `tened tube `due to the folded margins'thereof. This result is achieved by the feature of loose `on the work consists solely of the weight of the Vjournaling of the discs 36 onthe rod 33 which enable-s said discs to assume independent posi'- discs 36, which press the tube against the'driven r.

roller I8 to feed the tube longitudinally in the,

directionindicated by the arrow in Fig. 3.

For supporting the endless tube Il in an 'open loop while it is being progressively pressed, as

shown, a pair of idler supporting rollers 42, 42 is provided. Said rollers are in parallel, spaced apart relation, and have -a horizontal operative position somewhat above the' contour roller 3|, as shown in Figs. 3 and 4, and have a vertical linoperative position (not shown) within the upper housing I5, the opening 32 in the front wall of swinging said rollers in unison about their pivots.

The rollers 42 are so positioned with relation to` the contour roller `3| that when they are in their lowered, inoperative position'y they will be disposed on opposite sides of the contour roller er 3I upon the tube I I, the latter is pressed into frictional'driving engagement with the driven roller I8 and impelled longitudinally by the latter. The pressure `of the roller 3| alsoflattens the tube II transversely thereof, as shown in Fig. 4, and forces opposite sides thereof locally into face to face Contact with each other, thus forcing the viscous proofing composition in the tube to be spread over the interior surface thereof, progressively about the entire tube. This phase of operation continues until every part of the tube has passed between the rollers I8, 3I at least twice.` Thereafter' the contour roller 3I rises from the work and assumes its inoperative vertical position, and then the idler rollers 42 move to their inoperative vertical position, during which movement their free ends move downwardly. This enables work unit I I to fall therefrom onto the rotating drive roller I8 and conveyor belts 23, the latter carrying the work to the far end of the frame I6 where it drops from 'the apparatus. The idler rollers move back to operative horizontal position before the apparatus ceases operation. y

The invention results'in the uniform distribu- `tion of viscous proofing composition throughout vthe interior of the work, and achieves the other 'tube by splicing to produce an endless tube having a closed internal'chamber in which the proofing composition is contained, evenly distributing the proong composition o'ver the interior'of'the tube, mounting a valve stem in the tube, and thereafter vulcanizing the rubber of the-tube.

2. The method of making inner tubes which comprises placing a determinate quantity of proofing composition within a length of unvulcanized rubber tubing, splicing the ends 0 f `the tube to make it endless and provide a closed internal chamber in which -the proofing composition is contained, impelling the tube circumfer- `entially and applying rolling pressure thereto in a local region of its path of movement to distribute the proong'composition evenly over'the entire interior surface of thetubefmounting a valve stem in the tube, and thereafter vulcanizing the rubber of the tube.

v GEORGE E. STEINEL. 

